1. Field of the Invention
The present invention relates to a making method of sample for evaluation of laser irradiation position and a making apparatus thereof. In the method and apparatus, while a semiconductor substrate is sequentially irradiated with a pulse laser beam, a portion to be irradiated with the laser beam, of the semiconductor substrate, is moved in a predetermined moving direction at a modifying treatment speed to continuously increase regions irradiated with the pulse laser beam on the semiconductor substrate. In addition, the present invention relates to an evaluation method of stability of laser irradiation position and an evaluation apparatus thereof. In the method and apparatus, stability of laser irradiation position is evaluated on the basis of the sample for evaluation of laser irradiation position, which is obtained by the making method of sample for evaluation of laser irradiation position or the making apparatus thereof.
2. Description of the Related Art
Modification of semiconductor with laser irradiation means that an amorphous semiconductor is crystallized with laser irradiation; a size of crystal grains of crystal semiconductor is increased with laser irradiation; defects in crystal grains of crystal semiconductor are reduced with laser irradiation; amorphous portions among crystal grains of crystal semiconductor are crystallized with laser irradiation; or an effect combining the above effects is obtained with laser irradiation. FIG. 12A illustrates a structure of a laser irradiation device 40 which performs modifying treatment of semiconductor. FIG. 12B is a view viewed along arrows B-B in FIG. 12A. In modification of semiconductor, as illustrated in FIGS. 12A and 12B, a portion to be irradiated with a pulse laser beam, of a semiconductor substrate 1 is moved in a predetermined moving direction at the modifying treatment speed while the semiconductor substrate 1 is sequentially irradiated with the pulse laser beam at a predetermined repetition rate by the laser irradiation device 40 so that regions irradiated with the pulse laser beam on the semiconductor substrate 1 are continuously increased. In general, a pulse laser beam is adjusted so that a cross-sectional shape perpendicular to the moving direction of the laser beam is long (for example, rectangular or linear) like a shape represented by dotted lines in FIG. 12B by a laser shape adjusting optical system 41, and the semiconductor substrate 1 is irradiated with the pulse laser beam. Therefore, a shape of a portion to be irradiated with the laser beam is also long. Movement of a region irradiated with the pulse laser beam is, for example, as illustrated in FIGS. 12A and 12B, performed by moving a stage 42 on which the semiconductor substrate 1 is put in the moving direction by a moving device 43 while the semiconductor substrate 1 is irradiated with the pulse laser beam. Accordingly, a desired range of the semiconductor substrate 1 is irradiated with the pulse laser beam. Such a laser irradiation device (laser annealing device) is described in Patent Document 1 (Japanese Published Patent Application No. 2002-158186), for example.
In some cases, a semiconductor substrate which is irradiated with a pulse laser beam by the above-described laser irradiation device has irradiation unevenness. The term “irradiation unevenness” means that the number of irradiation of pulse laser beam is different from region to region on the semiconductor substrate. For example, in FIG. 13, the region with a dark color shows a region irradiated with the pulse laser beam many times, and the region with a light color shows a region irradiated with the pulse laser beam far fewer times than the region with a dark color.